Electric hammer



June 30, 1931. E. G. bUELLHORST 1,812,271

ELECTRIC HAMMER Filed. Dec. 20, 1929 2 Sheets-Sheet 1 &

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= 9 V flamaazm Attorney June 30, 1931. E. a, QUELLHORST 1,312,271

ELECTRIC HAMMER Filed Dec. 20, 1929 2 Sheets-Sheet 2 pwwm A iiomey Patented June 30, 1931 UNITED STATES PATENT OFFICE Application filed December 20, 192 9. Serial No. 415,447.

This invention relates to electrical appliances and tools, and has more particular reference to an electric motor driven hammer with general utilitarian purposes.

Briefly, the invention has reference to a small portable electric hammer including an electric motor, a carrying handle therefor, and a mechanism barrel associated with the motor, the arrangement being such as to afford a unique, simplified and economical arran ement of parts.

y principal aim is to Upon tools of this class by providing one which is characterized by a distinguishable arrangement of parts structurally cooperating in producing a tool which is compact and convenient in arrangement, susceptible of easy manipulation, and otherwise developed to fulfill the requirements of an implement of this class in a highly satisfactory and efficient manner.

In the drawings:

Figure 1 is a top plan view of a hammer constructed in accordance with the present invention.

Figure 2 is a central longitudinal sectional view through the same.

Figures 3 and 4 are cross sections on the lines 33 and 4-4 respectively of Figure 2. Figure 5 is an enlarged fragmentary detail section on the line 5-5 of Figure'2.

Figure 6 is a section on the line 6-6 of Figure 5.

Figure 7 is a front view of one of the details.

The general assembly may well be seen in Figure 2 wherein it will be observed that the reference character 8 designates a small generally improve portable electric motor of appropriate power.

The motor includes a housing embodying a body section 9 having flanges 10 and 11 at its opposite ends. A cap 12 is bolted to the flange 11. Also, the int-urned extremities 13 of a handle forming bail 14 are secured 4 to the same flange by the same bolt, thus makof a square shaft 26.

ing for compactness and convenience in arrangement.

It might be stated that the handle is provided with a suitable switch of the construction shown in Figures 5 and 6. The handle is hollowed out to provide recesses to accommodate the parts. One recess serves to accommodate the button which is in the nature of a plate 15 pivoted in a recess and having pin and slot connection as at 16 with a movable contact rod 17. The free end of the rod is positioned to move between the contact 18 in which the electric wires (not shown) are connected.

The numeral 19 designates a spring which serves to hold the button 15 in the projected position seen in Figure 6. Merely pressing the button 15 in, serves to move the rod 17 between the contact 18 to close the circuit and set the motor 8 into operation.

Bolted to the flange 11 is a disc-like head plate 20 to which a. spacing ring 21 is fastened. The ring serves to space the plate 20 from a similar plate 22. The plate 22 has an eccentric screw threaded socket 23 receiving the screw threaded end of the cylindrical barrel 24. Interposed between the plates 20 and 22 is a gear 25 carried by the left hand end The spindle on the left hand end of the shaft is journalled in a hearing in the plate 20.

The motor shaft is provided with pinion 27 in mesh with the gear 25 rotating the shaft 26. The right hand end of the barrel is formed with a reduced conical guide 28. The stem portion 29 of a plunger is slidable in this guide and projectab-le beyond the right hand end thereof. The plunger includes a body portion 29 slidable in the barrel and having a central socket 30 receiving the adj acent end of the square shaft 26. This forms a slidable joint for the plunger. Thus the plunger is rotated and in addition is allowed to slide back and forth in a reciprocatory 0o formed with a conical guide 1 raining silliitllllj u 'liaceiiimeans shown. V

For instance, the portion 31 of the plunger is provided with a spiral thread 32 receiving the end portion 33 of a guiding and releasing'screw. It will be noted that the ad-' jacent ends of the threads are spaced apart longitudinally to permit the desired I'GCIPI'O-r catory action of the (plunger. The plunger is actuated by a coile spring 34 arranged in the barrel and bearing at one end against the body 29 and at its opposite end against an adjustable follower ring end portion of the barrel.

In operation, it is obvious when the motor is set in motion by closing the switch, the gearing 25 and 27 will serve to rotate shaft 26. This will in turn rotate the plunger, the plunger being held by the spring in a position to maintain the thread 32 in contact .with the relatively stationary release and guide screw 33. Thus, as the plunger turns around, it will be fed in the compressed spring, and at certain moments in the period of rotation, as the end of the thread passes screw 33', the spring will quickly snap the plunger outwardly forcing the tool stem 29 against the work in a reciprocatory manner.

From the foregoing description and drawings it will be seen that I have evolved and produced a simple and practical arrangement of parts structurally co-related. in forming a manner, the stroke being governed by the 7 formed with the plunger and reduced stem, a

35 in the left hand shaft, an intermediate portion integrally spiral thread forme on said intermediate portion, said thread having its ends longitudinally spaced, a guide and releasing screw mounted in said barrel, and cooperating with the spiral threads for permitting intermittent reciprocation of the plunger, and a coil spring hearing at one end against the follower plate and at the opposite end against the body portion of the plunger.

In testimon whereof I afiix my signature.

ELWIN EORGE QUELLHORST.

novel electrically-driven hammer, the same being portable, powerful, easy to manipulate, easy to repair, and otherwise susceptible of accomplishing the desired aim in a practical manner.

Persons skilled in the art to which the in vention relates will be able to obtain a clear understanding of the same after considering the description in connection with the drawings. Therefore, a more lengthy description is regarded as unnecessary.

Minor changes in shape, size,'and rearrangement of details coming within the field of invention claimed may be resorted to in actual practice if desired.

I claim: I

- In an electric hammer of the class described, a cylindrical barrel having one end and having the opposite end open and internally and externally screw threaded, a bearing and gearing assembly detachably mounted on the ex.- ternally screw threaded portion of 'said barrel, a follower ringadjustably mounted on the interior of the barrel and engaged with the internal. screw threads, a. shaft mounted for rotation in the bearings and operatively connected with the gearing, a rotatable and reciprocatory plunger in the opposite end portioii of the barrel including a reduced stem slid-able throughsaid conical guide, and also including a body portion having a socket re end of said 

